Heredity and Evolution Access Biology

Taxonomy, Phylogeny and Systematics Click on image to play

Through natural selection and artificial selection, Darwin discovered that organisms came from other organisms and were modified slowly through adaptations and variations. This theory gave birth to the idea of Phylogeny

The study of the evolutionary history of organisms. Phylogeny The study of the evolutionary history of organisms.

Introduction to Phylogeny and Cladograms Click on image for video

Classification groups species into larger categories that show descent…instead of just overall similarities and differences.

Cladograms help determine how closely related to a common ancestor an organism is. Click to view video

Cladograms Studying these cladograms helps us focus on certain traits, known as derived characteristics. Derived characteristics help us to better classify organisms. Claws, feathers, fangs, gills, etc…

What are Traits? Click on image to play video

Which traits do these organisms have? See corresponding worksheet

What information do you see looking at this cladogram?

Looking at this cladogram what characteristics are similar Looking at this cladogram what characteristics are similar? What do you hypothesize is their common ancestor?

Think about your family. You share certain traits that your parents passed down to you. Those traits were passed down by your grandparents! There are some fun traits that are inherited, rolling your tongue, which hand you write with. Can you name any others?

Who might this baby inherit his traits from?

Derived Characteristics All organisms carry DNA in their genes Genes are a derived characteristic We inherit genes from earlier generations.

This is an example of a 3 generation family tree Our traits may be derived characteristics from our family. Think of your family members and how They would be placed on a family tree. This is an example of a 3 generation family tree

Who is on your family tree? Discuss as class and then complete worksheet family tree

Sometimes, as an organism evolves, it loses traits Sometimes, as an organism evolves, it loses traits. So if four legs is a derived trait, the snake having no legs is a lost trait. Losing traits

Looking at this image, what are the different traits they may have lost?

A Phylogeny of Beasties You will reconstruct the evolutionary history of a group of imaginary organisms known as Beasties. The Beasties are a diverse group, and you will take advantage of this diversity. Refer to worksheet A Phylogeny of Beasties

Examine the specimens. How many characters can you identify? Make a list of these characters, along with short descriptions of their various states. Complete corresponding worksheet

Learn more about plant and animal traits at Floridastudents.org